Pressure operated switch with inertial locking means



June 3, 1958 Filed Feb. 6. 1957 R. L. DETWILER EVAL PRESSURE OPERATED SWITCH WITH INERTIAL LOCKING MEANS 2 Sheets-Sheet 1 l0 Q' r' Q 1 Il N s v 2 DI l() fr 3| S; m 3 8 o LD 0') n?) N ID a 3 /J .M me wf w/ 'wv 3% g gl .N %g 85" m /N N ,N l I Je NQ 2 m S2 N INVENToRs R. L. DETWILER A. N. BIRMINGHAM BY s. H'. KAUFFMAN June 3, 1958 R. Dr-:TwlLER ETAL 2,837,611

PRESSURE OPERATED SWITCH WITH INERTIAL LOCKING MEANS Filed Feb. 6, 1957 v2 Sheets-Sheet 2 FIG.3.

FIGA.

INVENToRs R. L. DETWILER A. N. BIRMINGHAM BY j s. H AUFFMAN United States Patent O PRESSURE OPERATED SWITCH WlTH INERTIAL LOCKING MEANS Robert L. Detwiler, Airfred N. Birmingham, and Samuel H. Kaulman, Silver Spring, Md., assignors to the United States of America as represented by 'the Secn retary of the Navy Application February 6, 1957, Serial No. 638,664

13 Claims. (Cl. 20D-83) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to a switching device operated by hydrostatic pressure and more particularly to a pressure operated switch which incorporates inertial locking means to prevent unintentional or fortuitous operation of the switch when the same is subjected to impact forces.

ln ordnance devices ot' the marine type, such as mines, y

An object of the present invention is the provision of a pressure operated switch which has incorporated therein inertial means preventing operation of the switch as a result of impact forces.

Another object is to provide a pressure operated switch having a rod formed with a conical cam surface, a circular series of balls in engagement with the cam surface, and a movable counterweight against which the balls react.

A further object is the provision of a pressure operated switch of the snap action type and an inertial weight cooperating therewith and serving to counter impact forces tending to cause operation of the switch.

Still another object is to provide a switch operated by hydrostatic pressure in which a Flexible diaphragm transmits hydrostatic pressure to movable parts of the switch and seals the switch against the entry of water therein.

A still further object is the provision of a switch operated by hydrostatic pressure and having a piston movable in a cylindrical bore and a flexible diaphragm secured to t the piston and to the wall of the bore, said diaphragm in the operated position of the switch being supported by the piston and bore wall and effective to seal the switch while submerged in great depths of water.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when -considered in connection with the accompanying drawings in which like reference numerals designate like parts throughout the figures thereof and wherein:

Fig. l is a longitudinal sectional view of one embodiment of the switch of this invention, the switch being shown in unoperated condition;

Fig. 2 is a view similar to Fig. l, but in which the switch is shown in operated condition;

Fig. 3 is a longitudinal sectional view of a snap action ICC type switch in which the inertial locking means of this invention is incorporated, the switch being shown in unoperated condition; and

Fig. 4 is a view similar to Fig. 3, but with the switch shown in partially operated condition.

Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in Fig. l a switch operated by hydrostatic pressure and designated generally by reference numeral ll. The switch il is comprised of a tubular casing 12 which is formed internally with a longitudinal series of bores of different diameters, for reasons which will hereinafter become more clearly apparent. Two such bores, designated by numerals i3 and 14 respectively, are located adjacent one end of the casing, bore 13 being of greater diameter than bore 1411, whereby a shoulder l5 is formed therebetween.

Disposed within bores i3 and 14 is a hollow member 16 having a central cylindrical bore 1'7 within which a piston 18 is adapted to move. Member it? is `formed with opposing end portions it? and 2l, and an intermediate portion 22, the external diameter of end portion 19 being greater than portion 22. and end portion 2l having a smaller diameter than portion 22. The diiierence in diameters of portions and provides a shoulder therebetween which is adapted to engage shoulder Member 16 is retained in the casing and sealed therein by means of a threaded retaining ring 23, a flexible diaphragm 2d and an O-ring seal 25, the O-ring seal engaging the wall of bore i4 and being disposed in a groove or channel 26 within and around portion 22. One end of casing 12 is internally threaded, as at 27, and receives the threaded retaining ring 23 which is adapted to be screwed into abutting engagement with member 16 and hold the same in place.

Diaphragm 24 is provided with a thickened periphery 28 which is received between member 1o and ring 23, in suitable recesses or notches 29 formed therein respectively, and has a central projection El received in a depression or recess 32 in piston i8 and cemented therein. Member 16 is formed with an internal annular recess along the walls of which a portion 34 of the diaphragm is adapted to be flattened, when the switch has been operated, as more suitably shown in Fig. 2. The dimensions of the diaphragm 24 and the recess 33 are so chosen that, in the operated condition of the switch, the lattened disposition of lthe diaphragm, as shown in Fig. 2, is obtained, and the diaphragm is backed up or supported by rigid structure throughout its er ent, whereby danger of rupture of the diaphragm, duc to high hydrostatic pressure forcing through unsupported parts of the diaphragm, is practically eliminated and the diaphragm is therefore effective in sealing the switch when the s.. ie is employed in great depths of water.

Secured to piston 18, and movable therewith, is an operating rod 35 extending toward the other end of the casing, the free end portion 36 of the rod being threaded and having nutwasher means 37 thereon. End portion 36 of the rod carries a sleeve 33 of insulating material which supports an annular member 39 of metallic or electroconductive composition, member 39 being provided with a plurality of knife blades 41 of conductive material, each blade being adapted to enter between and wipingly engage apair of conductive spring metal contacts 42.

Each pair of contacts 42 is connected to a prong terminal 43 respectively, the contacts and terminals beinU supported by an annulus 44 of insulating material. Annulus 44 is disposed within a suitable annular recess at the end of casing 12, the recess being formed internally of case 12 with a shoulder 45, which engagingly seats the annulus 44. The casing l2 has an externally threaded end 46 upon which is received the ring serving to hold the annulus 44 in place.

Adjacent piston 18, operating rod 35 is formed with a conical cam surface l which converges toward the free end of the rod and merges with another conical cam surface 49 having a degree of convergence slightly greater than lthat of cam surface 43. Cam surface 49, yin turn, merges with an annular arcuate surface 51 which ares outwardly to a cylindrical surface 52, surfaces 49 and 51 defining an annular groove or recess 53.

Surface 52, during movement of the operating rod 35, travels within a bore 54 formed in a support and reaction member 55. Member 55 is provided with an annular projection 56 and a groove or channel 57 spaced from the projection. internally, casing 12 is formed with a projection S, of annular or spider-web conguration, which extends inwardly and is adapted to be received between projection S6 and a retainer 59 disposed in the groove or channel 57. Projection 56 is thus held in engagement with proiection S8, and member 55 is thus iixedly mounted in the casing. Member 55 has a surface 60 and a suitable aperture 61 through which operating rod 35 passes, the latter having a conforming portion bearingly supported by the walls of aperture 61.

Encompassed about member 55, and journaled for sliding movement thereon, is an inertial element or counter weight 62, the latter being formed with a converging portion 63 which extends beyond and overhangs one end of member 55, the converging portion being hollowed out and having a tapering internal cam surface 64. Element 62 is provided with an annular projection 65, and interposed between projection 65 and a shoulder 66 on portion 22 of member 16 is a coiled compression spring 67, the spring normally biasing or urging element 62 so projection 65 thereof is in seating engagement With projection S6, as shown in Fig. 1.

Cam surface 64 converges toward piston 18, i. e., in a direction opposite to the convergence of ysurfaces 48 and 49 of rod 35, the aforesaid surfaces and the surface of the adjacent end of member 55 generally defining an annular pocket in which a circular series of balls 68 is disposed, the balls reacting against said surfaces during operation of the switch, which will now be described.

ln the unoperated condition of the switch, the balls eS, as illustrated in Fig. l, are disposed in contact with cam surfaces 49 and 64 and the surface of the end of member S5. After hydrostatic pressure has built up sufficiently, piston 1S is forced longitudinally toward threaded end 46 of casing 12, and the balls 68 are displaced from cam surface 49 to engage cam surface 48, as shown in Fig. 2. lnitially, because of the difference in degree of convergence of surfaces 48 and 49, the force of the hydrostatic pressure must be sufhcient to overcome static inertia and cause the balls to ride up the steeper surface 49. As the balls ride up surface 49, they are forced outwardly against cam surface 64, the reaction causing element 62 to be moved towards member 16, against the bias or urging of spring 67. After the balls contact surface 455, which is less steep than surface 49 and permits the balls to ride up more easily, increase in hydrostatic pressure, due to the ordnance item containing the switch sinking in the water, rapidly moves the piston, and operating rod connected thereto, to the completely operated condition of the switch, as shown in Fig. 2.

During movement of the piston from the position shown in Fig. 1 to that shown in Fig. 2, the fold in the flexible diaphragm 24 (see Fig. l) is flattened out against the walls of recess 33 (see Fig. 2) with the result the diaphragm is substantially fully supportedby structure capable of withstanding high pressure, whereby danger of rupture of the diaphragm is practically eliminated.

The diaphragm and the Vrelation of `the balls to the cam surfaces, etc. are important aspects of the invention,

a threaded retaining ring 47, y

but the most important aspect thereof is the relation of the inertial element or counter weight 62 to the other parts and its function in cooperation therewith to prevent operation of the switch due to impact forces. For instance, should an ordnance item in which the switch is incorporated be inadvertently dropped and fall in such a way that the force of impact tends to cause the operating rod 35 to move longitudinally toward threaded end 46 of casing 12, the same force also tends to cause the inertial element 62 to remain with projection 65 thereof in engagement with projection 56, thereby resisting the outward movement of balls 63 and counteracting the longitudinal movement of the operating rod. Thus, the arming circuit of the ordnance item is not inadvertently or unintentionally closed. lt is to be noted that, if the ordnance device is inadvertently dropped so that threaded end 27 of casing 12 is faced toward the point of impact, the inertial force of the impact tends to drive rod 35 toward threaded end 27 and consequently away from terminal contacts 41 and 42 thereby rendering this type of impact ineffective to cause inadvertent closure of the switch, the extent of rearward travel of rod 35 being limited by abutment of sleeve 3S against surface 6G of member 55 and by abutment of opposing faces of members 62 and 16 providing the force of impact is of such suliiciency as to compress spring 67 to this extent.

.if desired, casing l2 may be provided with a groove or channel 69 therearound in which ring 71 of flexible material, such, for example, as an .f5-ring seal, may be disposed for obvious purposes.

Turning now to Figs. 3 and 4, there is shown therein a snap action switch itil in which the inertial element or counterweight of the instant invention has `been incorpcrated. rlhe snap action vswitch includes a casing 102,

threaded at one end to a hollow member 193 having a piston bore lll-ftherein in wl ich a piston 1% is adapted to move. The piston is sealed against the entry of moisture by means of a llexible diaphragm 1'36 secured to the piston by suitable means, such as screw and Washer means llll'. The diaphragm is formed with enlarged periphery 19S which is pressed into sealing engagement with member 1tl3 by a retainer means 109, as will be understood byviewing Figs. 3 and 4.

Threadedly secured to piston 10:5, as at 111, is an operating rod 112 formed with an enlargement 113 thereon in the shape of two conical portions 114 and 115 joined at their bases in a crest 116. 0n the free end portion of rod 112, there is carried a shorting ring 117 having a plurality of knife blades 11S adapted to enter between and wipingly engage spring contacts 119, which are supported in an insulating member 121 and electrically connected to pin terminals 122. Shorting ring 117 is insulated from operating rod 112 by an insulating sleeve 123, the latter being held on the rod by nut and washer means 124. Member 121 is retained by ring 12S threaded to the casing 162 at 126.

Operating rod 112 passes through an aperture 127 in a support and reaction member 128 supported within casing MP2 and threadedly connected thereto, as at 129.

Mounted for sliding movement on member 12S is an inertial element or counterweight 131 that is formed with a converging portion having a tapering cam surface 132. The space generally delined by surface 132, the surface of the end of member 128 and the lsurfaces of conical portions 114 and 115 constitute an annular pocket in which a circular series of balls 133 is housed. A coiled compression spring 134 encircles inertial element or weight 131 and an end portion of member 193, reacting therebetween and normally biasing or urging the element to the position shown in Fig. 3. A channel or groove 135 may be provided in casing 102 and a ring of flexible material 136 may be disposed therein for obvious purposes. Y

In the operation of the switch illustrated in Figs. 3 and-4, sufficient pressure on piston 19S causes enlargeassvgoit ment lf3 to move to the right, as viewed in Fig. 3, the conical portion F115 forcing the balls 133 outwardly. inasmuch as the balls cannot move in the direction of pressure because of contact with member 128 which remains stationary, the balls react against surface 132 and cam member 131 in the opposite direction against the bias of spring 131iuntil the crest 116 is disposed in line with the balls and the condition shown in Fig. 4 obtains. immediately afterwards, the balls come in contact with the surface of conical portion lili, and the stress built up in spring i342, by camming of member ffii, forces the balls inwardly and the operating rod is forced to the right, as viewed in Figs. 3 and 4, with a snap action to close the switch, as will be understood by those skilled in the art.

inertial element or counterweight i3d is similar to inertial element 62 of the switch of Fig. l, and functions similarly to counter or cancel the edect of an impact force tending to move the operating rod to the closed position of the switch.

In view of the foregoing, it should be apparent that a pressure operated switch has been provided in which inertial means are incorporated which counter or prevent operation of the switch as a result of impact and in which a flexible diaphragm is related to supporting structure to eliminate danger of rupture of the diaphragm when the switch is employed in great depths of water.

Obviously many modifications and variations of the present invention are possible in light of the above teachings. it is therefore to be understood that the invention may be practiced otherwise than as specifically describe.

`What is claimed as new and desired to be secured by Letters Patent of the United States is:

l. ln a switch of the class disclosed, an operating rod movable in one direction to operate the switch to closed position, said rod having an enlargement thereon including a conical portion having an external tapered cam surface which converges in said one direction, a movable inertial means surrounding said rod and normally urged in said one direction to a seating position, said inertial means having a tapered interior cam surface which converges in a direction opposite to said one direction, said cam surfaces generally facing each other, fixed means cooperatively disposed with respect to said cam surfaces and defining a pocket therebetween, force transmitting means disposed in said pocket, movement of said rod in said one direction imparting outward movement to said force transmitting means, said outward movement of the force transmitting means reacting against said fixed means and said interior cam surface to move said inertial means away from its seating position, said inertial means serving to counter the effect of `an impact force acting to urge said rod and inertial means in said one direction, whereby outward movement of said force transmitting means is prevented and said operating rod is locked against movement in said one direction.

2. ln a switch as claimed in claim 1, further characterized in that said external cam surface includes a portion thereof which has a greater degree of convergence than the remainder thereof.

3. In a switch as claimed in claim 2, further characterized in that said force transmitting means is in contact with the aforesaid portion of the external cam surface in the unoperated condition of the switch.

4. In a switch as claimed in claim l, further characterized in that said enlargement includes another conical portion having a tapered cam surface which converges in a direction opposite to said one direction, said conical portions being joined together at the bases thereof in a crest.

5. A switch of the class disclosed, comprising, in combination, a casing, a member secured in said casing and having a piston bore therethrough, a piston supported for movement in said bore, an operating rod secured to said piston and movable therewith, a cylindrical member lixedly mounted in said casing and having a lateral projection, said rod extending through said cylindrical member, said rod being formed with an enlargement having a pair of tapered exterior cam surfaces, an inertial means mounted for sliding movement and encompassing the cylindrical member and said rod, a spring normally urging said inertial means to seat against said projection, said inertial means having a tapered interior cam surface, said cam surfaces and the surface of one end of said cyiindrical member generally defining an annular pocket, and a circular series of force transmitting elements disposed in said pocket, said elements being always in contact with the surface of said one end of the cylindrical member and with said interior cam surface of the inertial means, said elements also being in contact with one of said exterior cam surfaces of the enlargement in the unoperated condition of the switch and in contact with the other of said exterior cam surfaces in the operated condition of the switch.

6. A switch as defined in claim 5, wherein said pair of tapered exterior cam surfaces converge in the same direction with one of the last-named surfaces having a greater degree of convergence than the other.

7. A switch as defined in claim 5, wherein said pair of tapered exterior cam surfaces meet in a line, said exterior cam surfaces diverging toward each other from points beyond said line, whereby said line constitutes a crest.

8. A switch as defined in claim 5, wherein said inertial means comprises a hoilowed out tapered portion and a cylindrical bearing portion journaled on said cylindrical member, said inertial means having a lateral projection adapted to seat against the lateral projection of the cylindrical member, and said spring being a coiled compression spring which encircles said inertial means with one end of the spring engaging said lateral projection of the inertial means.

9. A hydrostatic pressure operated switch of the class disclosed, comprising, in combination, a casing, a support xed in said casing, said support having an aperture axially of the casing, an operating rod extending through said aperture and supported for sliding movement therein, said rod being formed with an exterior cam surface thereon, a spring pressed element disposed about said support and slideable thereon, said element having an opem'ng through which said rod extends, said element adjacent the opening thereof being formed to provide a tapered interior cam surface, said cam surfaces and the surface of one end of said support dening a pocket, force transmitting means disposed in said pocket and contacting the surfaces defining the pocket, movement of saidrod serving to cam the force transmitting means outwardly and slide said element relative to said support, a piston secured to said rod, a member having a bore in which said piston is supported for sliding movement, and a flexible diaphragm secured at its central portion to said piston, the periphery of said diaphragm being secured in sealing relation to said member, said diaphragm having the intermediate portion thereof folded back upon itself in the unoperated condition of the switch.

10. A switch as defined in claim 9, wherein said member has an annular recess therein in which said intermediate portion is disposed, said intermediate portion being adapted to be flattened against the walls of said recess in the operated position of the switch, whereby the switch may be employed in great depths of water without danger of rupture of the diaphragm due to non-support thereof.

ll. An anti-impact snap action switch, comprising, in combination, a generally cylindrical support member having a coaxial bore therein, a rod movable axially in said bore and having a double cam enlargement, said enlargement being formed of two conical portions joined at their bases in a crest, a cup-like inertial Weight surrounding said member and slideable axially thereon, said weight having an opening accommodating said enlargement and formed interiorly with an annular cani surface adjacent said opening, a circular series of elements disposed at one end of said member in engagement therewith and contacting said cam surface and said enlargement, and a spring encircling said weight and urging the same in one direction to a seated position, said elements in the unoperated position of the switch contacting one of said conical portions with the crest and other conical portion being disposed on the side of the elements opposite to said one direction, movement of the enlargement in said one direction in response to pressure on the rod imparting outward movement to said elements, said outward movement causing said eicments to react between said end of the member and said cam surface to move said weight against the urging of said spring, movement of the crest past said elements bringing the other conical portion into contact with said elements for impelling the rod in said one direction to an operated condition of the switch, movement of said rod in said one direction due to impact with the switch in unoperated condition being countered by the inertial Weight tending to remain in seated position during impact and to resist outward movement of said element and thereby prevent movement of the crest past the elements.

12. In a switch of the class disclosed, the combination comprising a iXed cylindrical support, a rod extending axially thereof and journaled for sliding movement therein, said support having an end surface, an endless line of balls disposed in contact with said end surface, a cylinder-like inertial element surrounding said support and journaled thereon for axial sliding movement, said element having a portion extending beyond said end u: surface and overhanging said balls, said portion having a tapered interior cam surface converging toward said rod and in contact with said balls, said rod having a tapered cam enlargement thereon opposite in convergence to the cam surface of the inertial element, and a spring connected to said inertial element and urging the same in the direction of convergence of the tapered cam enlargement, movement of said rod in said direction servin'J to cam said balls outwardly which in turn cam the inertial element in a direction opposite to said rstnamed direction, an impact force tending to move said rod in the direction to cam said balls outwardly also tending to move said inertial element in the same direction and prevent outward camming of the balls for locking the rod against movement.

13. A pressure operated switch comprising a rod movable in one direction in response to pressure, and means operatively engaging said rod for locking said rod against movement in response to an impact force acting in said one direction, said means including inertial means movable in a direction opposite to said one direction in response to said movement of the rod and acting in said one direction in response to said impact force, said inertial means being yieldably urged in said one directlon.

References Cited in the le of this patent UNlTED STATES PATENTS 2,099,416 Aikman Nov. 16, 1937 2,386,162 Hetherington Oct. 2, 1945 2,659,381 Seljos Nov. 17, 1953 2,766,497 Noyes Oct. 16, 1956 2,775,665 Harstrclc Dec. 26, 1956 FOREGN PATENTS 13,721 Great Britain Apr. 2, 1914 

